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Biomedical subjects

James R Kasser

Publications and source records attributed to James R Kasser.

14 recordsLinked to original sources
PubMed2006

Osteotomy does not improve early outcome after slipped capital femoral epiphysis.

We performed a retrospective, nonrandomized cohort study of unilateral, chronic, severe, stable slipped capital femoral epiphysis comparing five girls and five boys who underwent in-situ screw fixation alone with five girls and five boys who underwent in-situ screw fixation combined with staged flexion intertrochanteric femoral osteotomy to restore proximal femoral alignment. Functional outcome was measured by the Harris hip score, with 20% selected as a goal for improvement in functional outcome after corrective osteotomy. While flexion intertrochanteric femoral osteotomy improved hip range of motion, we found no significant difference in functional outcome between the two groups at early follow-up. This is a level 3 evidence study.

Adolescent↗
PubMed2005

Serum levels of nickel and chromium after instrumented posterior spinal arthrodesis.

STUDY DESIGN: Cross-sectional study of 37 patients to measure serum levels of nickel and chromium after posterior spinal arthrodesis using stainless steel implants. OBJECTIVES: To investigate the relationship between factors such as age, gender, pain, time from surgery, length of arthrodesis, and level of arthrodesis to serum metal ion levels after instrumented spinal arthrodesis. SUMMARY OF BACKGROUND DATA: Measurable levels of metal ions in the serum can be detected after the use of stainless steel implants. There is some evidence to suggest that long-term exposure can potentially be toxic. Posterior spinal arthrodesis with stainless steel implants is a common procedure to treat spinal deformity in the adolescent population; however, the extent of metal ion exposure after posterior spinal arthrodesis is unknown. METHODS: Patients that underwent posterior instrumented spinal arthrodesis with more than 6 months follow-up were recruited for this study. Patients with altered neurologic function were excluded. Serum levels of nickel and chromium were measured using inductively coupled plasma mass spectrometry. Pain was assessed using the Oswestry questionnaire. Spine radiographs were used to look for evidence of pseudarthrosis. Forty-five patients were approached, and 37 agreed to the questionnaire and blood test. Ten patients were men and 27 were women. Mean age at surgery was 14 years with mean follow-up of 6 years. Statistical correlations between serum metal ion levels and age at surgery, time from surgery, gender, number of segments fused, spinal instrument interfaces, pain, and instrumentation type were assessed. RESULTS: Abnormally high levels of nickel and chromium above normal levels (0.3 ng/mL for nickel, 0.15 ng/mL for chromium) could be detected in serum after posterior spinal arthrodesis using stainless steel implants. There was a significant inverse correlation between serum nickel (r = -0.61, P < 0.001) and chromium (r = -0.64, P < 0.001) levels and time from surgery. When patients were grouped based on lengths of time from surgery, 0 to 2 years (n = 7), 2 to 4 years (n = 11), and >4 years (n = 8), the mean +/- SD for nickel (ng/mL) was 3.8 +/- 2.6, 1.3 +/- 1.1, and 0.9 +/- 0.8, respectively. Analysis ofvariance revealed significant group differences (P =0.004). Similarly, the chromium levels were 2.7 +/- 2.7, 0.6 +/- 0.4, and 0.3 +/- 0.3, respectively (P = 0.018). Only time from surgery was a significant multivariate predictor of nickel and chromium serum levels. Pseudarthrosis was not seen in this cohort. CONCLUSIONS: Elevated levels of nickel and chromium can be measured after posterior instrumented spinal arthrodesis. The levels diminish rapidly with time from surgery but still remained above normal levels 4 years after surgery. Long-term implication of this metal ion exposure is unknown and should be studied further.

Adolescent↗
PubMed2005

Location of treatment of supracondylar fractures of the humerus in children.

A change in the locations where children are treated for supracondylar fractures of the humerus has occurred during the past 13 years. Pediatric orthopaedic surgeons at specialist centers are seeing an increased number of such fractures. In New England, the number of supracondylar fractures of the humerus treated by closed reduction and percutaneous pinning has remained relatively constant between 1991 and 1999 with a range of 276 to 346 fractures per year, averaging 320 per year. In 1991, 63% of patients were treated by general orthopaedic surgeons in a nonspecialist setting. By 1999, 68% of the fractures were treated at centers with pediatric orthopaedic specialists available whereas only 32% were treated in a general orthopaedic setting. Associated with this change is a decreased length of stay from 2.2 (+/- 0.6) days in nonspecialist centers to 1.4 (+/- 0.4) days average in specialist centers.

Age Distribution↗
PubMed2004

Delay in diagnosis of slipped capital femoral epiphysis.

OBJECTIVE: Delay in diagnosis of slipped capital femoral epiphysis (SCFE) has important implications in terms of slip severity and long-term hip outcome. The purpose of this study was to identify predictors of delay in the diagnosis of SCFE. METHODS: A review of 196 patients with SCFE was performed. The primary outcome measure was delay from onset of symptoms to diagnosis. Covariates included age, gender, side, weight, pain location, insurance status, family income, slip severity, and slip stability. Delay in diagnosis was not normal in distribution; therefore, nonparametric univariate and multivariate analyses were performed. RESULTS: The median delay in diagnosis was 8.0 weeks. There was a significant relationship between delay in diagnosis and slip severity (<30 degrees : 10.0 weeks; 30 degrees to 50 degrees : 14.4 weeks; >50 degrees : 20.6 weeks). There were no significant associations between delay in diagnosis and covariates of age, gender, side, and weight. There were significant associations between longer delay in diagnosis and covariates of knee/distal-thigh pain versus hip/proximal-thigh pain (6.0 vs 15.0 weeks), Medicaid coverage versus private insurance (12.0 vs 7.5 weeks), lower family income, and stable slips versus unstable slips (8.0 vs 6.5 weeks). Controlling for the other covariates, knee/distal-thigh pain, Medicaid insurance, and stable slips remained significant independent multivariate predictors of delay in diagnosis. CONCLUSIONS: Patients who present with primarily knee or distal-thigh pain, patients with Medicaid coverage, and patients with stable slips have longer delays in diagnosis of SCFE. Focused intervention programs to reduce the delay in diagnosis of SCFE should emphasize patients with knee/thigh pain and patients with Medicaid coverage.

Child↗
PubMed2004

Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children.

BACKGROUND: The differentiation between septic arthritis and transient synovitis of the hip in children can be difficult. The purpose of the present study was to validate a previously published clinical prediction rule for this differentiation in a new patient population. METHODS: We prospectively studied children who presented to a major children's hospital between 1997 and 2002 with an acutely irritable hip. As in the previous study, diagnoses of septic arthritis (fifty-one patients) and transient synovitis (103 patients) were operationally defined on the basis of the white blood-cell count in the joint fluid, the results of cultures of joint fluid and blood, and the clinical course. Univariate analysis and multiple logistic regression were used to compare the two groups. The predicted probability of septic arthritis of the hip from the prediction rule was compared with actual distributions in the current patient population. The area under the receiver operating characteristic curve was determined. RESULTS: The same four independent predictors of septic arthritis of the hip (a history of fever, non-weight-bearing, an erythrocyte sedimentation rate of 40 mm/hr, and a serum white blood-cell count of >12,000 cells/mm(3) (>12.0 x 10(9)/L)) were identified in the current patient population. The predicted probability of septic arthritis of the hip from the prediction rule was similar to the actual distributions in the current patient population. The area under the receiver operating characteristic curve for the current patient population was 0.86, compared with 0.96 in the original population. CONCLUSIONS: Clinical prediction rules typically demonstrate diminished performance in a new patient population because they are optimally modeled to the original data set. The previously published clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children demonstrated diminished, but nevertheless very good, diagnostic performance in a new patient population.

Algorithms↗
PubMed2004

Prophylactic pinning of the contralateral hip after unilateral slipped capital femoral epiphysis.

BACKGROUND: The management of the contralateral hip after unilateral slipped capital femoral epiphysis is controversial. The purpose of this study was to determine, with use of expected-value decision analysis, the optimal management strategy-prophylactic in situ pinning versus observation-for the contralateral hip. METHODS: Outcome probabilities were determined from a systematic review of the literature. Utility values were obtained from a questionnaire on patient preferences completed with use of a visual analog scale by twenty-five adolescent male patients without slipped capital femoral epiphysis. A decision tree was constructed, fold-back analysis was performed to determine the optimal treatment, and one and two-way sensitivity analyses were performed to determine the effect on decision-making of varying outcome probabilities and utilities. RESULTS: Observation was the optimal management strategy for the contralateral hip given the outcome probabilities and utilities that we studied (the expected value was 9.5 for observation and 9.2 for prophylactic in situ pinning, with a marginal value of 0.3). Increased rates of a late second slip favored prophylactic in situ pinning (the threshold probability was 27%). Risk-taking patients with a high utility for uncomplicated prophylactic in situ pinning favored prophylaxis (the threshold utility was 9.8). CONCLUSIONS: The iatrogenic risks of treating a healthy patient or an uninvolved body part rarely outweigh the potential benefits unless the probability of the adverse event is likely and the consequences of the adverse event are very severe. In this decision analysis, the optimal decision was observation. In cases where the probability of contralateral slipped capital femoral epiphysis exceeds 27% or in cases where reliable follow-up is not feasible, pinning of the contralateral hip is favored. For a given individual patient, the optimal strategy depends not only on probabilities of the various outcomes but also on personal preference. Thus, we advocate a model of doctor-patient shared decision-making in which both the outcome probabilities and the patient preferences are considered in order to optimize the decision-making process. LEVEL OF EVIDENCE: Economic and decision analysis, Level III-1 (limited alternatives and costs; poor estimates). See Instructions to Authors for a complete description of levels of evidence.

Bone Nails↗
PubMed2004

Analysis of 51 tibial triplane fractures using CT with multiplanar reconstruction.

OBJECTIVE: We determined the most common patterns of triplane fractures and assessed the risk of epiphyseal separation in each pattern. MATERIALS AND METHODS: Fifty-one children with tibial triplane fractures underwent CT, and the resultant scans underwent multiplanar reconstruction. We categorized epiphyseal and physeal involvement, the number of fragments, the appearance of the Salter-Harris fracture in each plane, and the degree of separation of the epiphyseal fragments. RESULTS: The classic two-fragment type of fracture with medial epiphyseal extension occurred most frequently (33/51). All three-fragment types (8/51) of fractures resulted in a separate anterolateral fragment. Extension to the medial malleolus was common (12/51). None of the four reported fractures types involving anteromedial physeal separation was seen. Children with epiphyseal separation requiring surgery were older (odds ratio [OR] = 1.7) and had plafond involvement (OR = 5), CONCLUSION: CT and multiplanar reconstruction of triplane fractures improve the understanding of patterns of injury and their relative prevalence.

Adolescent↗
PubMed2003

Osteopetrosis.

Osteopetrosis is a rare skeletal condition characterized by skeletal sclerosis caused by aberrant osteoclast-mediated bone resorption. Three clinically distinct forms of osteopetrosis are recognized--the infantile malignant autosomal recessive form, the intermediate autosomal recessive form, and the adult benign autosomal dominant form. The disease represents a spectrum of clinical variants because of the heterogeneity of genetic defects resulting in osteoclast dysfunction. The pathogenic defects may be intrinsic to either the osteoclast-monocyte lineage or the mesenchymal cells that constitute the microenvironment that supports osteoclast ontogeny and activation. Implicated factors include specific proto-oncogenes, growth factors, and immune regulators. A subset of patients with the intermediate autosomal recessive form has been characterized with carbonic anhydrase II isoenzyme deficiency. Management of patients with osteopetrosis requires a comprehensive approach to characteristic clinical problems including hematologic and metabolic abnormalities, fractures, deformity, back pain, bone pain, osteomyelitis, and neurologic sequelae. Medical treatment of osteopetrosis is based on efforts to stimulate host osteoclasts or provide an alternative source of osteoclasts. Stimulation of host osteoclasts has been attempted with calcium restriction, calcitrol, steroids, parathyroid hormone, and interferon. Bone marrow transplant has been used with cure for infantile malignant osteopetrosis. As osteopetrosis likely represents a spectrum of underlying etiologies resulting in osteoclast dysfunction, effective therapies most likely need to be individualized.

Humans↗
PubMed2003

A clinical practice guideline for treatment of septic arthritis in children: efficacy in improving process of care and effect on outcome of septic arthritis of the hip.

BACKGROUND: The development of clinical practice guidelines is a central precept of the evidence-based-medicine movement. The purposes of this study were to develop a guideline for the treatment of septic arthritis in children and to evaluate its efficacy with regard to improving the process of care and its effect on the outcome of septic arthritis of the hip in children. METHODS: A clinical practice guideline was developed by an interdisciplinary expert committee using evidence-based techniques. Efficacy was evaluated by comparing a historical control group of thirty consecutive children with septic arthritis of the hip managed before the utilization of the guideline with a prospective cohort group of thirty consecutive children treated with use of the guideline. Benchmark parameters of process and outcome were compared between groups. RESULTS: The patients treated with use of the guideline, compared with those treated without use of the guideline, had a significantly higher rate of performance of initial and follow-up C-reactive protein tests (93% compared with 13% and 70% compared with 7%), lower rate of initial bone-scanning (13% compared with 40%), lower rate of presumptive drainage (13% compared with 47%), greater compliance with recommended antibiotic therapy (93% compared with 7%), faster change to oral antibiotics (3.9 compared with 6.9 days), and shorter hospital stay (4.8 compared with 8.3 days). There were no significant differences between the groups with regard to other process variables, and there were no significant differences with regard to outcome variables, including readmission to the hospital, recurrent infection, recurrent drainage, development of osteomyelitis, septic osteonecrosis, or limitation of motion. CONCLUSIONS: Patients treated according to the septic arthritis clinical practice guideline had less variation in the process of care and improved efficiency of care without a significant difference in outcome.

Anti-Bacterial Agents↗
PubMed2002

Prospective reevaluation of the association between thrombotic diathesis and legg-perthes disease.

BACKGROUND: Legg-Perthes disease is associated with ischemia of the capital femoral epiphysis in children. Thrombophilia has been implicated as a potential cause of the condition, and screening of patients with Legg-Perthes disease for thrombophilia has been recommended. We analyzed the value of screening for inherited thrombophilia in patients with Legg-Perthes disease by examining the association between Legg-Perthes disease and abnormalities in the thrombotic pathway. METHODS: A random series of consecutive patients with Legg-Perthes disease were prospectively enrolled in this study. Assays for the detection of factor-V Leiden mutation and the plasma concentrations of protein C, protein S, antithrombin III, and lipoprotein (a) were performed on plasma samples from children with Legg-Perthes disease, and the results were compared with those for pooled plasma from normal controls. Plasma concentrations below the 95% midrange of the control values were classified as protein deficiencies. The estimated population frequency of each coagulation abnormality was compared with the proportion of the study group with the corresponding abnormality. RESULTS: The proportion of abnormalities observed in the study group did not differ from the estimated population frequency for protein C, protein S, antithrombin III, or factor-V Leiden mutation. A lipoprotein (a) level of >30 mg/dL (>1.07 micro mol/L) was found in 16% of the study group. CONCLUSIONS: Our data do not suggest that thrombotic diatheses due to deficiency of protein C, protein S, or antithrombin III or due to factor-V Leiden mutation are major causes of Legg-Perthes disease. The elevated levels of lipoprotein (a) in children with Legg-Perthes disease suggest that they may be at risk for atherosclerosis as adults.

Anticoagulants↗
PubMedDate not supplied

Virtual reality simulation of arthroscopy of the knee.

The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces known as "PHANToMs" that also monitor the position of the instruments in the user's hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software provides the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee. This includes moderating the haptic interface and simultaneously executing a collision-detection algorithm that prevents the instruments from moving through "solid" surfaces. Modeling software interacts with this algorithm to send the appropriate images to the video display, including knee pathology such as meniscal tears and chondral defects as well as normal anatomy. Task-oriented programs monitor specific performance such as executing a proper examination of the knee or shaving a torn meniscus.

Arthroscopy↗
PubMedDate not supplied

Hip arthroscopy in children and adolescents.

Hip arthroscopy has become an established procedure for certain indications in adults, but experience in children and adolescents has been more limited. The purpose of this study is to report the early-term results of hip arthroscopy in children and adolescents. A consecutive case series of 54 hip arthroscopies in 42 patients 18 years old and younger over a 3-year period at a tertiary-care children's hospital with a minimum of 1 year of follow-up was reviewed. Patients were assessed with the modified Harris hip score (HHS) before and after surgery. Overall results and results by common diagnoses were analyzed. Indications for surgery included isolated labral tear (n = 30), Perthes disease (n = 8), hip dysplasia with labral tear after prior periacetabular osteotomy (n = 8), inflammatory arthritis (n = 3), spondyloepiphyseal dysplasia (n = 2), avascular necrosis (n = 1), slipped capital femoral epiphysis (n = 1), and osteochondral fracture (n = 1). Overall, there was a significant improvement in HHS from 53.1 to 82.9 (P < 0.001), with 83% of patients improved. By diagnosis, significant improvement in HHS was seen for patients with isolated labral tears undergoing labral debridement (before surgery 57.6; after surgery 89.2; P < 0.001), for patients with Perthes disease undergoing chondroplasty and loose body excision (before surgery 49.5; after surgery 80.1; P < 0.001), and for patients with hip dysplasia after prior periacetabular osteotomy undergoing labral debridement (before surgery 51.8; after surgery 79.8; P < 0.001). Complications included transient pudendal nerve palsy (n = 3), instrument breakage (n = 1), and recurrent labral tear (n = 3). Hip arthroscopy in children and adolescents appears to be safe and efficacious for certain indications in the short term.

Adolescent↗
PubMedDate not supplied

Proximal femoral epiphysiolysis during reduction of hip dislocation in adolescents.

Traumatic hip dislocation is an uncommon injury in children. The urgency of closed reduction to prevent possible osteonecrosis may present some pitfalls. Adolescents with open proximal femoral physis may have sustained trauma to the physis at the time of dislocation that can lead to displacement of the epiphysis during the reduction maneuver. The purpose of this study is to report 5 cases with this complication and discuss potential etiology and management. All of the 5 patients were between 12 and 16 years old and underwent closed reduction under conscious sedation. Epiphysiolysis of the femoral head was diagnosed after reduction in all 5 patients. Every patient underwent emergent open reduction and internal fixation of the femur and open hip reduction. Avascular necrosis was identified in all 5 patients within 3 to 15 months postinjury. If there is any suspicion of associated physeal injury or if there is any physeal instability noted under fluoroscopy, an open reduction is recommended in the operating room under radiograph guidance to prevent displacement.

Adolescent↗